Many light fixtures are controlled by a single switch. In these cases, it is standard practice that the switches are mounted such that the toggle element is in a raised position when the light is energized and in a lowered position when the light is not energized. In some cases, however it is necessary for light fixtures to be controlled by multiple switches. For example, the National Electrical Safety Code (NESC) requires that a stairway have a switch at each end of the stairway to energize the lighting in that space. In situations where multiple switches control the same light fixture(s), those switches must be multiway switches.
Due to the inherent design of current multiway switches, such multiway switches do not share the aforementioned standard practice that the switch's toggle element is in a raised position when the light is energized and in a lowered position when the light is not energized. Rather, a multiway switch's toggle element may be in either a raised or lowered position when the light is energized. Conversely, a multiway switch's toggle element may be in either a raised or lowered position when the light is not energized. Additionally, a multiway switch's toggle element may be in the raised position when the light is energized, but at a later time still be in the raised position, though with the light no longer energized.
The aforementioned lack of correlation between switch position and light energization causes the user a number of inconveniences. In such instances, a user may observe the toggle element of multiway switch in the raised position when the light is not energized. As such, the user may mistakenly conclude that the light is burned out.
Often multiple light switches are grouped together at a single location. A user wanting to turn off all of the lights in a particular area may place all the switches' toggle elements in the lowered position to accomplish this. However, if one or more multiway switches are present the user may inadvertently energize a light fixture.
Users may instinctively sweep their hand or arm over the toggle element of a light switch in an upward or downward manner without looking at the switch because the state of the light leads them to believe that the toggle element should be in a certain position. When a multiway switch is present, the toggle element may be in a position that the user does not expect, rendering their motion ineffective.
Users may also sweep their hand or arm over the toggle element of a light switch in an upward or downward manner when they cannot see the toggle element, such as in a dark room. As in the previous case, this motion may be ineffective.
Users may desire to control a light fixture that is out of sight, such as a light that is on the other side of a door. Users will be compelled to move to a location to where they can observe the state of the light to confirm that they have placed the light in the desired state.
Because this lack of correlation between the toggle element position and the energization of the light exists, users may also question the state of switches which are not multiway switches. As it is not readily apparent whether a switch is a multiway switch or a regular switch, users may doubt the status of a switch that does indeed have a correlation between switch position and energization of the light.
U.S. Pat. No. 3,238,343 issued to Carlson attempted to address this shortcoming with an illuminated pushbutton. However, this solution required extra wiring and introduced an interface that was unfamiliar to the user.
Given these factors, there is a clear need for a switching apparatus that overcomes the limitations of the prior art.